Quick release sear for light machine guns



Nov. 28, 1961 R. H. COLBY 3,010,237

QUICK RELEASE SEAR FOR LIGHT MACHINE GUNS Filed Oct. 5, 1960 2Sheets-Sheet l I. F1 l3 4-5 14 I 4/ 4 W in, 42 6O 72 Li 'lll l 4 4s 2 64\L A 55 22 38W 74 62 66 30 f \36\ 2s I i i- Fi .4- 1 18 2? 14 I 14 h 184 7O 16 20 x 4 t i 52 7a 24 4 22 ag 22 58 I I I\ g. 8 40 g/ 5 & 36 26 62zo l 3 3o \32 I INVENTOR. 3 28 Hnfimr d HEmnJy 2/. 7901206; #Q -QQW Nov.28, 1961 R. H. COLBY QUICK RELEASE SEAR FOR LIGHT MACHINE GUNS FiledOct. 5, 1960 2 Sheets-Sheet 2 INVENTOR. Rial-11nd Hljuuzly BY 1 1-2224;

El E6 tats The invention described herein may be manufactured and usedby or for the Government for governmental purposes without the paymentof any royalty thereon.

This invention relates to automatic firearms and more particularly tothe trigger mechanisms thereof.

One of the hazards oftentimes encountered with automatic firearms is arun-away gun where the operator loses control of the firing because thesear and/or the sear notch in the sear controlled member are worn to theextent that the operating mechanism cannot be stopped by the sear whenreleased by the trigger mechanism.

One of the causes of this excessive wear is that the operators generallydo not return the trigger to nonfiring position quickly enough toprevent rasping contact between the searing portions before completesearing is achieved. In the past, devices have been provided whichachieve a quick release of the sear by mechanical means, but thesedevices are actuated by the operating member controlled by the sear andare generally complicated in design and operation.

It is, therefore, the principal object of this invention to provide aquick release sear which is controlled entirely by the cooperatingtrigger and which is released with the same speed regardless of howslowly the trigger is released by an operator.

It is also the purpose of this invention to provide a quick release searwhich is simple in design, easy to manufacture and is positive inoperation.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

FIG. 1 is a longitudinally cross-sectioned view of the trigger mechanismof this invention showing the trigger in normal position and theoperating rod latched in the recoil position thereof by the sear;

FIG. 2 is a view similar to FIG. 1 but showing the trigger actuated tothe firing position and the sear in its disengaged position;

FIG. 3 is a view taken along line 3-3 of FIG. 1;

F1G.-4-is a view taken along line 4-4 of-FIG. 2; and

FIG. 5 is a perspective, exploded view of the trigger mechanism.

' Shown in the figures is a light machine gun 12 having a reciprocaloperating rod 14 which is arranged for actuating the operating mechanism(not shown) of the gun and which is actuatable inrec'oil andcounterrecoil strokes between a recoil and a battery position. Operatingrod 14 is spring-biased 'by conventional means (not shown) to thebattery position and is releasably held in the recoil position by atrigger mechanism 16 mounted on the undersideof a receiver 18. v

Trigger mechanism 16 includes a trigger housing 20 having a longitudinalchannel 22 disposed along the top thereof in which channel a scar 24 anda trigger 26 are mounted for cooperation as hereinafter described. Atrigger guard 28 is provided at the bottom front end of trigger housing20 to form a clearance 30 into which a fingerpiece 32 of trigger 26depends to provide means for manual actuation thereof as hereinafterdescribed. The rear side of clearance 30, noted at 34, extendsvertically downward in trigger housing 20 from the bottom of 3,010,237Patented Nov. 28, 1961 channel 22. As trigger housing 20 may befabricated from a light and relatively soft metal, there is provided atthe junction of side 34 and the bottom of channel 22 an insert 36 whichis made of steel and which has a purpose to be more fully explainedhereinafter. Insert 36 forms a longitudinal ledge 38 and a front face 40which extends downwardly at right angles from the front edge thereof.

Sear 24 is of bar configuration with a rectangular crosssection and islongitudinally disposed in channel 22 immediately below operating rod14. Sear 24 is rockingly mounted approximately midway the length thereofon a transverse pin 42 so as to be pivotal between an engaging and adisengaged position. The rear end of sear 24 forms a latch portion 44which, when the sear is in the engaging position, is receivable by anotch 46 in operating rod 14 for releasably securing the operating rodin the recoil position. A spring 48 is disposed between the underside ofsear 24, rearwardly of pin 42-, and the bottom of channel 22 for biasingthe sear to the engaging position.

Provided vertically through sear 24 forwardly of pin 42 is a rectangularaperture 52 which receives a scar latch 54. Sear latch 54 is mounted inaperture 5 2 by means of a transverse axle 56 so as to be pivotalbetween a blocking and a release position. The lower end of sear latch54, noted at 58, extends below sear 24 so as to be engageable with ledge38 of insert 36 so that, when the sear latch is in the blockingposition, sear 24 is prevented from moving out of the disengagedposition. When sear latch 54 is in the release position, lower end 58thereof is swung clear of ledge 38 and is displaced downwardly alongfront face 40 thereof to permit actuation of scar 24 by spring 48 to theposition in engagement with operating rod 14. A spring 60 is disposedbetween sear latch 54, above axle 56, and the rear wall of aperture 52for biasing the sear latch to the blocking position.

Trigger 26 includes a substantially rectangular bod portion 62 fromwhich fingerpiece 32 integrally depends. Trigger .26 is pivotallymounted in trigger housing 20 forwardly of scar latch 54 and below thefront end of scar 24 by means of a pin 64 which traverses channel 22 andthe front upper corner of body portion 62. Fingerpiece 32 extends intoclearance 30 by means of an opening 66 which provides communicationbetween such clearance and channel 22. A vertical recess 68 bifurcateslongitudinally the top rear corner of body portion 62 and such recessreceives a roller 70 which is axially mounted on a transversal shaft 72and is disposed so as to project above the top of trigger 26 for rollingcontact with the underside of the front end of sear 24. Whereby, whenfingerpiece 3 2 is pulled rearwardly, trigger 26 pivots about pin 64 toraise roller 70 against the front end of sear 24 which is pivotedthereby from the engaging to the disengaged position; J

A spring-biased plunger 74 is housed within fingerpiece 32 and isarranged so as topress against side 34 of clearance 30 for biasingtrigger 26 forwardly from a firing to a nonfiring position. The end offingerpiece 32 is received by a recess 76 in trigger guard 28 and theengagement of the fingerpiece with the ends of therecess limits themovement of trigger 26 between the firing and nonfiring positionsthereof.

A pair of wings 78 extend rearwardly from the sides of body portion 62so as to be laterally spaced and such' wings are connected at the rearends by a laterally disposed bar 80. Bar 80 is spaced rearwardly fromthe rear end of body portion 62 sufficiently to form a clearance 82 forreceiving lower end 58 of scar latch- 54 and is disposed to pull suchlower end from ledge 38 during the return of trigger 26 to the nonfiringposition.

Thus, when trigger 26 is in the nonfiring position and operating rod 14is latched in the recoil position thereof, as illustrated in FIG. 1,sear latch 54 is positioned by bar 80 on the trigger so that lower end58 of the sear lease operating rod 14- to initiate a burst of fire.-When the front end of sear 24 is elevated by trigger 26, sear latch 54is also elevated so that, when the sear reaches the disengaged position,lower end 58 of the sear latch is raised clear of front face 40 of ledge38. Whereupon,

sear latch 54 is biased to the blocking position by spring 60 so thatlower end 58 is 'rearwardly displaced over ledge 38. Consequently, whenfi-ngerpiece 32 is permitted to go forwardly to stop'the firing-burst,the contact of lower end 58 with ledge 38 blocks the pivotaldisplacement of sear 24 from the disengaged position until trigger'26 isdisplaced sufficiently for bar 80 to pull the lower end of latch 54 fromledge 38. When lower end 58 is pulled clear of ledge 38 by bar 80, sear24 is instantly freed to be pivoted to the engaged position for stoppingthe reciprocation of operating rod 14 through the bias of spring 48.

From the foregoing it is clearly apparent that there is provided hereinfor a trigger mechanism a quick release sear which is positive inoperation, simple in design and is easy to manufacture.

Although a particular embodiment of the invention has been described in'detail herein, it is evident that many variations may be devised withinthe spirit and. scope thereof and the following claims are intended toinclude such variations. V

I claim:

1. In a machine gun having a reciprocating member,

a trigger mechanism including'a trigger housing, a sear pivotallymounted in said trigger housing for releasable engagement with thereciprocating member for initiating and stopping operation of the gun, atrigger pivotally disposed in said trigger housing for operationalcooperation with said sear to transfer displacement of said trigger to afiring position into pivotal displacement of said sear to a position indisengagement from the member, a ledge formed in said trigger housing, asear latch pivotally pivot-ally mounted'rin said trigger housingby meansof a in the disengaged position thereof, and means carried by saidtrigger for pulling said sear latch out of contact with said ledgeresponsive to displacement of said trigger from ,the firing position forquick release of said sear to the position for engagement with themember. 7

3. The trigger mechanism as defined in claim 2 wherein said triggerincludes a substantially rectangular body pin which is transverselydisposed through'said trigger housing andthrough. said body at the fronttop corner thereof, a verticalrece ss disposed for bisecting longitudinally the top rear cornerof said body, and a roller axially mountedin said recess-so as to be displaceable against said sear for convertingpivotal displacement of said trigger to the firing position to pivotaldisplacement of said sear to a position out of. engagement with the V amember.

4. The trigger mechanism as defined in claim 2 wherein.

said Sean is provided with a vertically disposed aperture therethrough,said sear latch is pivotally mounted in said aperture for displacementbetween the blocking-and release positions thereof and a spring isdisposed between.

sear latch to the'blocking position.

5. In a machine .gun havinga reciprocating member, a trigger mechanismincluding a trigger housing provided said sear latch and a wall of saidaperture for biasing said with a channel disposed longitudinally alongthe top thereof, a sear mounted in .said channel on a first pin disposedtransversely through said searapproximately midway the length thereoffor pivotal displacement between an engaging and' a disengaged position,a latch portion 3 disposed at the rear end. of said sear forreleasable'en gagement with a notch in the member for stopping thereciprocation thereof when said sear is in the engaging position, atrigger including a substantially rectangular bodyand a fingerpiecedepending therefrom, a second pin extending transversely through saidchannel and said body at the top front corner thereof to provide pivotaldisplacecarried by said sear, said sear latch being disposed forreleasable engagement with said ledge for blocking move pivotallymounted in said trigger housing .for releasable engagement withthe'member forinitiating andstopping operation of 'the'gun, means forbiasing said sear to a position for engagement with the member, atrigger displacement 'of 'said sear to' the disengaged position, an isaid trigger hou'singjso as to be engageable bygsaid sear latch when inthe blocking position to prevent movement mounted in said triggerhousing for pivotal displacement between a firing and a nonfiringposition, means on said trigger for converting displacement thereof tothe firing position to pivotal displacement of said sear to a positionout of engagement with the member, a sear latch mounted on said sea-rfor pivotal displacement between a blocking and a release position,meansfor biasing said sear'latch to the'blocking position, a ledgeformed in said trigger housing so as to be contactable by said searlatch when in the blocking position for releasably holding said sear.

ment' of said trigger from a firing to a nonfiring position, a;vertically disposed recess for bisecting longitudinally the top rearcorner of said body, a roller axially mounted on ashaft transverselydisposed through said recess,; said roller being engageable with theunderside of said sear forwardly of said first pin fortransferring-pivotal displacement ofwsaid trigger to the'firing positionto pivotal aperture verticallydisposed through said searforwardly ofsaid first pin, a sear latch mounted in saidtaperture on a transversalaxle for pivotal displacement between a blocking and a release position,a spring disposed between 7 said sear latch anda-wall of said aperturefor'biasing said sear latch to the blocking position, aledge-disposedinof. said sear to'a position engagement with the member," and a bardisposed on said trigger for displacement against said searlatch-for-pullingjsaid' sear latch clear of said ledge to thereleaseposition for. quickrelease of said sear to the engaged position.during displacement of said trigge r't o the nonfiring position.

References C itedin the file of this patent UNITED STATES PATE Ts *12,509,540, s nda -m... -Mt 'so, i950 7 awn-

